Abstract:The new lines Nanhua 5, Nanhua 11, Shanyou 39, and Shanyou 59, are high-yield lines derived from the F1 hybrid rice, Nanyou 2 and Shanyou 2 by means of tissue culture and selec- tion. Five isozymes, esterase, peroxidase, ATP-ase, malate dehydrogenase and glulamate dehydrogenase from the new lines, the F1 hybrid rices and their parents, were analyzed by starch and polyacrylamid gel electrophoresis. There are no difference in zymogrames of ATPase, malate dehydrogenase, glulamate dehydrogenase, between the F1 hybrid and its parents. But the F1 hybrid rice contains complemental bands of anodal esterase EA2, EA3 and cathodal esterase EC1, EC2, EC3, EC4, The esterase zymogram of seeds of Nanhua 5, Nanhua 11 and Shanyou 39, Shanyou 59 could be observed in the progeny of the F2 hybrid rice. The results indicated that the new lines would be possibly derived from the progeny of the F1 hybrid by means of tissue culture and selection.